In a device of this type, the motor-driven fan unit, also called impeller, includes a casing housing a centrifugal turbine driven by a motor so as to deliver a pressurized airflow to an outlet duct. This airflow next passes through an air filter then a heating-refrigeration unit mounted downstream and including heat exchangers (radiator and evaporator, if appropriate) making it possible to heat or cool the air which will then be delivered to the passenger compartment via various ducts and distribution vents.
In the majority of known devices, the motor-driven fan unit, the air filter and the heating-refrigeration unit are placed in a generally aligned configuration, which increases the overall size of the device. Moreover, such a configuration does not always allow easy removal of the air filter to make it possible, at regular intervals, to check the state of the filter and to exchange a used filter for a new filter.
Various filter configurations have already been proposed with a view to facilitating removal. Hence, it is known to remove the air filter from the passenger compartment, as taught, for example, by DE-A-40 04 501 and FR 2 731 657. However, access to the filter from the passenger compartment is generally difficult, and the instrument panel does not always have sufficient space available to arrange a cover plate in it for accessibility to the filter.
Otherwise, the document EP 0 744 309 teaches that it is possible to gain access to the air filter from the water separator. However, this location is generally constricted, so that the insertion and the positioning of the filter downstream of the water separator is not generally easy. Moreover, the stopper enclosing the filter should be perfectly impervious to water.
Moreover, these known solutions do not make it possible to reduce the size of the device.
Consequently one object of the invention is to propose a heating and/or air-conditioning device possessing a reduced size, especially in the direction of the longitudinal axis of the vehicle, while providing means allowing easy removal of the air filter.